Systems and methods for treating aneurysms

ABSTRACT

An apparatus for treating an aneurysm includes an occlusion element configured to be releasably coupled to an elongate delivery shaft and including an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, the occlusion element configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter and further configured to expand to an expanded configuration when advanced out of the delivery catheter, wherein in the expanded configuration, at least the outer layer of the inverted mesh tube is formed into an expanded shape including a proximal section having a first transverse dimension, a distal section having a second transverse dimension, and a waist portion having a third transverse dimension, wherein the third transverse dimension is less than the first transverse dimension, and the third transverse dimension is less than the second transverse dimension, and wherein in the expanded configuration, the waist portion is configured to be deformed by an externally applied force such that a distance between the distal section and the proximal section is decreased.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/840,421, filed on Apr. 5, 2020, which claims the benefit of priorityto U.S. Provisional Patent Application No. 62/852,988, filed on May 25,2019, U.S. Provisional Patent Application No. 62/914,442, filed on Oct.12, 2019, U.S. Provisional Patent Application No. 62/975,741, filed onFeb. 12, 2020, and U.S. Provisional Patent Application No. 62/975,744,filed on Feb. 12, 2020, all of which are herein incorporated byreference in their entirety for all purposes. Priority is claimedpursuant to 35 U.S.C. § 120 and 35 U.S.C. § 119.

BACKGROUND OF THE INVENTION Field of the Invention

The field of the invention generally relates to embolic devices forfilling spaces in the vascular system, including cerebral aneurysms orleft atrial appendages. In some case, the embolic devices may be used toembolize native vessels.

Description of the Related Art

An embolic device may be used as a stand-alone device to occlude andaneurysm, or may be used with an adjunctive device or material.

SUMMARY OF THE INVENTION

In one embodiment of the present disclosure, an apparatus for treatingan aneurysm in a blood vessel includes an occlusion element configuredto be releasably coupled to an elongate delivery shaft, the occlusionelement including a mesh body configured to be delivered in a collapsedconfiguration through an inner lumen of a delivery catheter, the innerlumen having a proximal end and a distal end, the body furtherconfigured to expand to an expanded configuration when advanced out ofthe distal end of the inner lumen of the delivery catheter and into theaneurysm, wherein the body includes a proximal portion having a proximalmaximum transverse dimension A and a distal maximum transverse dimensionB and a frustoconical portion extending between the proximal maximumtransverse dimension A and the distal maximum transverse dimension B,and wherein the body further includes distal portion having a maximumtransverse dimension C and a waist portion between the proximal portionand the distal portion, and wherein the dimension A is between about 50%and about 100% of dimension B.

In another embodiment of the present disclosure, an apparatus fortreating an aneurysm in a blood vessel includes an occlusion elementconfigured to be releasably coupled to an elongate delivery shaft, theocclusion element including an inverted mesh tube having an outer layerand an inner layer, the outer layer transitioning to the inner layer atan inversion fold, wherein at least the outer layer is formed into anexpanded shape having a proximal section having a first diameter, adistal section having a second diameter, and a waist portion having athird diameter, wherein the third diameter is less than the firstdiameter and the third diameter is less than the second diameter.

In yet another embodiment of the present disclosure, an apparatus fortreating an aneurysm in a blood vessel includes an occlusion elementconfigured to be releasably coupled to an elongate delivery shaft, theocclusion element including an inverted mesh tube having an outer layerand an inner layer, the outer layer transitioning to the inner layer atan inversion fold, wherein at least the outer layer is formed into anexpanded shape having a proximal section having a first diameter, adistal section having a second diameter, and a first waist portionhaving a third diameter, a middle section having a fourth diameter, anda second waist portion having a fifth diameter, wherein the firstdiameter, the second diameter, and the fourth diameter are each greaterthan the third diameter, and wherein the first diameter, the seconddiameter, and the fourth diameter are each greater than the fifthdiameter.

In still another embodiment of the present disclosure, a method forforming an apparatus for treating an aneurysm in a blood vessel includesforming a mesh tube, inverting the mesh tube to form an outer layer andan inner layer, the outer layer transitioning to the inner layer at aninversion fold, forming at least the outer layer into an expanded shapehaving a proximal section having a first diameter and a distal sectionhaving a second diameter, and etching the distal section to decrease itsstiffness.

In yet another embodiment of the present disclosure, an apparatus fortreating an aneurysm in a blood vessel includes an occlusion elementconfigured to be releasably coupled to an elongate delivery shaft, theocclusion element including an inverted mesh tube having an outer layerand an inner layer, the outer layer transitioning to the inner layer atan inversion fold, the occlusion element configured to be delivered in acollapsed configuration through an inner lumen of a delivery catheter,the inner lumen having a proximal end and a distal end, the occlusionelement further configured to expand to an expanded configuration whenadvanced out of the distal end of the inner lumen of the deliverycatheter and into the aneurysm, wherein in the expanded configuration,at least the outer layer of the inverted mesh tube is formed into anexpanded shape including a proximal section having a first transversedimension, a distal section having a second transverse dimension, and awaist portion having a third transverse dimension, wherein the thirdtransverse dimension is less than the first transverse dimension, andthe third transverse dimension is less than the second transversedimension, and wherein in the expanded configuration, the waist portionis configured to be deformed by an externally applied force such that adistance between the distal section and the proximal section isdecreased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an occlusion device according to anembodiment of the present disclosure.

FIG. 2 is a sectional view of the occlusion device of FIG. 1.

FIG. 3 is a sectional view of an alternative occlusion device, accordingto an embodiment of the present disclosure.

FIG. 4 is a sectional view of an alternative occlusion device, accordingto an embodiment of the present disclosure.

FIG. 5 is a sectional view of an alternative occlusion device, accordingto an embodiment of the present disclosure.

FIGS. 6-9 illustrate the implantation of the occlusion device of FIG. 1in an aneurysm of a blood vessel of a patient.

FIG. 10 is a sectional view of an alternative occlusion device,according to an embodiment of the present disclosure.

FIG. 11 is a sectional view of an alternative occlusion device,according to an embodiment of the present disclosure.

FIG. 12 is a sectional view of an alternative occlusion device,according to an embodiment of the present disclosure.

FIG. 13 is a sectional view of an alternative occlusion device,according to an embodiment of the present disclosure.

FIG. 14 is an occlusion device according to an embodiment of the presentdisclosure implanted within an aneurysm.

FIG. 15 is an occlusion device according to an embodiment of the presentdisclosure implanted within an aneurysm.

FIG. 16 illustrates an occlusion device according to an embodiment ofthe present disclosure implanted within an aneurysm.

FIG. 17 illustrates an occlusion device according to an embodiment ofthe present disclosure implanted within an aneurysm

FIG. 18 illustrates an occlusion device according to an embodiment ofthe present disclosure.

FIG. 19 is a sectional view of an unrestrained occlusion deviceaccording to an embodiment of the present disclosure.

FIG. 20 is the occlusion device of FIG. 19 restrained within a deliverycatheter.

FIG. 21 is the occlusion device of FIG. 19 delivered into an restrainedwithin an aneurysm.

FIG. 22 is a sectional view of an occlusion device according to anembodiment of the present disclosure.

FIG. 23 is a side view of an occlusion device according to an embodimentof the present disclosure.

FIG. 24 is a plan view of an occlusion device according to an embodimentof the present disclosure.

FIG. 25 is a plan view of the occlusion device of FIG. 24 releasablycoupled to a pusher, according to an embodiment of the presentdisclosure.

FIG. 26 is a perspective view of the occlusion device of FIG. 24implanted within a simulated aneurysm, according to an embodiment of thepresent disclosure.

FIG. 27 is a perspective view of the occlusion device of FIG. 24implanted within a simulated aneurysm, according to an embodiment of thepresent disclosure.

FIG. 28 is a sectional view of an alternative occlusion device,according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Aneurysms are abnormal bulging or weakening of a blood vessel, often anartery, and can have many complications. A bulging of the blood vesselcan disrupt or put pressure on surrounding tissues. Cerebral aneurysmscan result in a variety of side effects, such as impaired vision,impaired speech, impaired balance, etc. Further, the aneurysm creates avolume that is not along the main flow path of the blood through theblood vessel. It therefore can serve as a location for blood to becomestagnant and, due to swirling eddy currents, can contribute to theformation of a thromboembolism. If an aneurysm ruptures, it can causesevere internal bleeding, which in cerebral arteries can often becomefatal.

Aneurysms can be treated externally with open surgery. Such procedurestypically involve closing off the entrance or “neck” of the aneurysmwith a device such as vascular clip, clamp or a ligature. However, suchopen surgical procedures can be highly invasive and may lead to traumato the adjacent tissue and other side effects.

Aneurysms can also be treated through endovascular procedures. In oneprocedure, detachable lengths of wires (e.g., coils) are inserted intothe interior volume of the aneurysm using a catheter. The coils areintended to fill the volume of the aneurysm to decrease the flow ofblood into the aneurysm, inducing stagnation of flow and stimulateclotting within the aneurysm. In settings of large cerebral aneurysms,filling of the aneurysm with multiple coils can lead to mass effect thatmay induce brain swelling and be an independent cause for new symptoms.In another procedure, for aneurysms with a relatively large neck, theadjunctive use of stents assists with the retention of the coils withinthe aneurysm. This approach may have a contraindication to being usedwhen treating ruptured aneurysm, due to the need for additionalanti-thrombotic medications. In another procedure, the coils are held inthe volume of the aneurysm with a temporary balloon that is inflated inthe blood vessel. The balloon is deflated and removed once the mass ofcoils is secured. In still another procedure, a stent device is placedin the artery to promote flow of blood past the aneurysm. This leads tostagnation of the blood within the aneurysm and thrombosis inside theaneurysm volume. However, a side branch of a main artery in which thestent device is placed may become trapped or “jailed,” which can impedeaccess to the side branch. In other instances, the side branch canbecome clotted off, possibly causing a stroke. Additionally, such aprocedure generally requires the use additional anti-thromboticmedications, which limits the use of such devices in the setting oftreatment of ruptured aneurysms. The stent device is often formed with arelatively tight weave. While the tight weave increases theeffectiveness of the stent device in diverting the blood flow, it alsoimpedes or prevents access to the volume of the aneurysm or the jailedartery. In the event that the aneurysm fails to clot, the obstruction ofthe aneurysm by the stent device prevents the possibility of placingembolic devices inside the aneurysm. Additional procedures such as theplacement of additional stents or open surgery may then be required totreat the residual.

Procedures that involve packing the volume of the aneurysm can sufferfrom several common shortcomings. First, it can take many coils of wireto fill the volume of the aneurysm, which is time consuming andincreases the time it takes to complete the procedure. Further, thecoils may be compacted over time to occupy a smaller percentage of thetotal volume of the aneurysm. A great enough compaction of the coils canbe considered a recurrence of the aneurysm and may require furthertreatment.

FIG. 1 illustrates an occlusion device 200 configured for placementwithin an aneurysm. The occlusion device 200 comprises a proximalsection 202 and a distal section 204, each constructed of a single,continuous dual layer mesh. Turning to FIG. 2, the occlusion device 200is constructed from an inverted mesh tube 206 having a first end 208, asecond end 210, and a wall 209. The inverted mesh tube 206 extends on anouter layer 212 from the second end 210 past a proximal end 214 of theproximal section 202 and along a proximal hemisphere shape 216 to amaximum diameter portion 218 having an acute angulation 219. From themaximum diameter portion 218, the outer layer 212 extends radiallyinward along a substantially flattened portion 220 to a central waist222. The outer layer 212 then extends radially outward along asubstantially flattened portion 224 of the distal section 204 to amaximum diameter portion 226 having an acute angulation 227 to a distalhemisphere shape 228 to a distal end 230 of the occlusion device 200.The hemisphere shape 228 is configured to contact at least a portion ofan aneurysm dome. The maximum diameter portion 226 has a diameter thatis about equal to the diameter of the maximum diameter portion 218, butin other embodiments, they may differ. The occlusion device 200 issubstantially cylindrically symmetric around a central axis Z. However,in alternative embodiments, there may be certain portions of asymmetry,such as one or more indented or extended feature at a particularlocation in a perimeter. At the distal end 230, the wall 209 is invertedinwardly at an inversion fold 232, which creates a distal orifice 234and an internal volume 236. The wall 209 transitions at the inversionfold 232 from the outer layer 212 to an inner layer 238 which followsthe contours of the outer layer 212 from the distal orifice 234 to thefirst end 208. The inner layer 238 follows a hemisphere shape 240, amaximum diameter portion 242 having an acute angulation 244, asubstantially flattened portion 246 of the distal section 204, a centralwaist 248, a substantially flattened portion 250 of the proximal section202, a maximum diameter portion 252 having an acute angulation 254, anda hemisphere shape 256. The occlusion device 200 is fabricated as aninverted mesh tube 206 having a simple straight elongate configuration,and is subsequently formed into the shape shown in FIGS. 1 and 2 andheat set into this shape. For example, the occlusion device 200 may beconstructed as a single layer mesh tube formed of at least somenickel-titanium alloy filaments, and then inverted on itself. Theinverted mesh tube 206 may then be placed into a die or mold comprisingone or more pieces, to hold it in the shape of the occlusion device 200.Then, the occlusion device 200 may be subjected to an elevatedtemperature and then cooled, to lock in the shape, resulting in anocclusion device 200 having at least some superelastic properties. Eachof the proximal section 202 and distal section 204 are configured to becompressed or compacted within the lumen 148 of a delivery catheter 150(e.g., microcatheter).

In some embodiments, one or both of the proximal section 202 or thedistal section 204 may comprise some nickel-titanium alloy filaments andsome radiopaque elements, comprising platinum, gold, tantalum, or alloysof any of these or other radiopaque materials. In some embodiments, thefilaments may comprise drawn filled tubes, such as those comprising anickel-titanium alloy outer wall and a platinum core. The radiopaquematerial allows the occlusion device 200 to be visible on radiographs orfluoroscopy. The occlusion device 200 may be configured by controllinghow much radiopaque material is used, by either the ratio of radiopaquefilaments to non-radiopaque filaments, or by the amount of platinum corein the drawn filled tubes. In this manner, the occlusion device 200 canbe selectively fabricated to be sufficiently visible, but not overvisible, e.g., overly bright, such that other objects are obscured. Insome embodiments, whether any of the filaments comprise radiopaquematerials or not, a marker band may be attached to the proximal end 214of the proximal section 202, by adhesive or epoxy bonding, or swaging,welding or other mechanical attachment.

FIG. 3 illustrates an occlusion device 260 also comprising an invertedmesh tube 262 and having an outer layer 264, an inner layer 266, and aninversion fold 268, which creates a distal orifice 270, and serves asthe transition between the outer layer 264 and the inner layer 266. Theinverted mesh tube 262 has a first end 284 and a second end 286. Theocclusion device 260 includes a proximal section 272 and a distalsection 274. The proximal section 272 and distal section 274 havesubstantially flattened portions 276, 278, and the distal section 274has a distal hemisphere shape 280, configured to contact an aneurysmdome. There is a waist 281 between the substantially flattened portions276, 278. The maximum diameter portion 279 has a diameter that is aboutequal to the diameter of the maximum diameter portion 277, but in otherembodiments, they may differ. The proximal section 272 includes aconcave cone shape 282, or circumferentially-extending concavity, whichmay be configured to direct blood flow, particularly when the occlusiondevice 260 is implanted within a bifurcation aneurysm or a terminalaneurysm, wherein the blood flow is directed along the paths of arrow288 or arrow 290. The occlusion device 260 may comprise any of thematerials and be made with any of the processes described in relation tothe occlusion device 200.

FIG. 4 illustrates an occlusion device 300 also comprising an invertedmesh tube 302 and having an outer layer 304, an inner layer 306, and aninversion fold 308, which creates a distal orifice 310, and serves asthe transition between the outer layer 304 and the inner layer 306. Theinverted mesh tube 302 has a first end 312 and a second end 314. Theocclusion device 300 includes a proximal section 316 and a distalsection 318. The proximal section 316 and distal section 318 havesubstantially flattened portions 320, 322, and the distal section 318has a distal hemisphere shape 324, configured to contact an aneurysmdome. There is a waist 321 between the substantially flattened portions320, 322. The maximum diameter portion 328, on the distal section 318,has a diameter that is larger than the diameter of the maximum diameterportion 326, on the proximal section 316, and thus, the occlusion device300 is configured to be implanted in an aneurysm having a larger dome(distal) portion and a smaller proximal portion of the aneurysm sac. Theproximal section 316 of the occlusion device 300 includes a partiallyconvex, partially concave shape 330 which may be configured to directblood flow along the concave portion 332, and also configured tointerface with the proximal portion of the aneurysm at the convexportion 334. Both the concave portion 332 and the convex portion 334face substantially proximally. The occlusion device 300 may comprise anyof the materials and be made with any of the processes described inrelation to the occlusion device 200.

FIG. 5 illustrates an occlusion device 340 also comprising an invertedmesh tube 342 and having an outer layer 344, an inner layer 346, and aninversion fold 348, which creates a distal orifice 350, and serves asthe transition between the outer layer 344 and the inner layer 346. Theinverted mesh tube 342 has a first end 352 and a second end 354. Theocclusion device 340 includes a proximal section 356 and a distalsection 358. The proximal section 356 and distal section 358 havecurvilinear portions 360, 362 facing each other, and the proximalsection 356 has a hemisphere shape 364, configured to contact a proximalwall of the aneurysm. The maximum diameter portion 368 of the distalsection 358 has a diameter that is smaller than the diameter of themaximum diameter portion 366 of the proximal section 356, and thus, theocclusion device 340 is configured to be implanted in an aneurysm havinga smaller dome (distal) portion and a larger proximal portion of theaneurysm sac. The distal section 358 includes a smaller hemisphere shape370. The occlusion device 340 may comprise any of the materials and bemade with any of the processes described in relation to the occlusiondevice 200.

In FIGS. 6-9, an aneurysm 10 having a neck portion 16 is shown. Theocclusion device 200 is shown in use being implanted by a user (e.g.,physician) into the aneurysm 10 through the delivery catheter 150 todisrupt or halt the flow of blood flow between the blood vessel 12 andthe internal volume 14 of the aneurysm, thereby reducing the likelihoodthat the aneurysm 10 will rupture (or if previously ruptured, reducingthe likelihood of rerupture). The occlusion device 200 is configured tobe low profile device, minimizing disruptions to surrounding bodies,such as a side branch 18 of the blood vessel 12. The blood vessel 12 hasa blood vessel wall 13 and the aneurysm 10 has an aneurysm wall 11. InFIG. 6, the delivery catheter 150 is advanced through a sheath and/orguiding catheter (not shown) through a puncture or cutdown in aperipheral blood vessel, such as a femoral artery, a brachial artery, ora radial artery. The distal end 162 of the delivery catheter 150 may beshaped with a curve, as shown, either by the manufacturer, or prior tothe procedure by the user, in order to allow for improved backup supportwhen delivering the occlusion device 200. The distal end 162 of thedelivery catheter 150 is placed adjacent the neck portion 16 of theaneurysm 10. The delivery catheter 150 may be advanced over a guidewire(not shown) that is passed through the lumen 148. The guidewire may thenbe removed, leaving the lumen 148 as a delivery conduit and the deliverycatheter 150 as a support column.

In FIG. 7, the occlusion device 200 is advanced through the lumen 148 ofthe delivery catheter 150, as described, and the distal section 204 ofthe occlusion device 200 is advanced out of the lumen 148 and into theinternal volume 14 of the aneurysm 10. The distal end 230 is the firstportion of the occlusion device 200 that exits the lumen 148 and thus isthe first portion of the occlusion device to enter the aneurysm 10. Thedistal end 230 is blunt, soft, and atraumatic and is configured to firstcontact the interior surface 15 of the aneurysm 10. In FIG. 8, theocclusion device 200 is shown in a substantially expanded configurationwithin the internal volume 14 of the aneurysm 10. The proximal section202 is expanded against the interior surface 15 of the aneurysm 10, andcovers the neck portion 16 of the aneurysm. The distal section 204 isexpanded against the interior surface 15 of the aneurysm 10, and servesto anchor or stabilize the proximal section 202 in the aneurysm 10 andadjacent the neck portion 16.

Also, in FIG. 8, the detachable joint 158 (see FIG. 7) has beendetached, and thus, the free end 154 of the pusher 152 can be pulledinto the lumen 148 of the delivery catheter 150. In some embodiments,the delivery catheter 150 is maintained over the detachable joint 158during the detachment procedure, to further protect the aneurysm 10. InFIG. 9, the delivery catheter 150 is removed, and the deployed occlusiondevice 200 is in place to begin to occlude the internal volume 14 of theaneurysm. The distal section 204 also serves to force the proximalsection 202 against the neck portion 16 and/or against the interiorsurface 15, see straight arrow in FIG. 9. The dual layer of mesh in theproximal section 202 at a lower portion 231 (FIGS. 2 and 9) aid in thedisruption of blood flow into the aneurysm 10, thus causing thrombosisto isolate the internal volume 14 of the aneurysm 10 from blood flowthrough the blood vessel. 12. The waist 222 helps the distal section 204transmit force to the proximal portion 202, though the maximum diameterportions 218, 226 are also configured to transmit force to thesubstantially flattened portions 220, 224, or the substantiallyflattened portions 220, 224 transmit to each other, as the waist 222 islongitudinally compressed. The force (straight arrow) maintaining theproximal section 202 in place, further assures this process, and alsoprotects against undesired compaction over time of the occlusion device200. The dual layers of mesh in the distal section 204 can aid in thehealing of the dome. In an unruptured aneurysm, the contact with thedome can cause healing that can thicken the dome at this portion, wherethe dome is often at is thinnest, most stretched state. In a rupturedaneurysm, the contact with the dome can act like a bandage andaccelerate or increase the healing process to further avoid are-rupture.

The occlusion devices 260, 300, 340 of FIGS. 3-5 are implanted intoaneurysms 10 in a similar manner to the occlusion device 200 describedin relation to the implantation procedure of FIGS. 6-9. Alternativeembodiments of the occlusion devices 200, 260, 300, 340 from FIGS. 1-5are shown in FIGS. 10-13. Occlusion devices 374, 376, 378, 380 are eachsimilar to occlusion devices 200, 260, 300, 340, respectively, exceptthat the inner layers 382, 384, 386, 388 do not follow the contours ofthe outer layers 390, 392, 394, 396, but instead are substantiallystraight tubular columns. These columns may be the diameter of theoriginal tubular mech (as braided), or may be an expanded diameter (asheat formed). The inner layers 382, 384, 386, 388 can each provideadditional column strength and longitudinal support, which can help toapply a force against the aneurysm neck portion 16 with the proximalsections 391, 393, 395, 397.

FIG. 14 illustrates an occlusion device 400 being implanted within anangulated sidewall aneurysm 19 having a dome 21 that is off axis fromthe neck portion 16. This may be approximated by angle A. The occlusiondevice 400 is similar to the occlusion device 200, and has a proximalsection 402 that is separated from the distal section 404 by an elongateflexible extension 406. The flexible extension 406 may be similar to thecentral waist 222 of the occlusion device 200, but the diameter and thelength may be varied in order to change its flexibility characteristics,and to change to total amount of angulation possible between theproximal section 402 and the distal section 404. The construction of theocclusion device 400 may be identical to any of the embodimentsdescribed in relation to the occlusion devices 200, 260, 300, 340, 374,376, 378, 380 of FIGS. 2-5 and 10-13, however, the longer, more flexibleextension 406 allows the distal section 404 to more readily angulatewith respect to the proximal section 402. It also allows for a largeramount of angulation between the proximal section 402 and the distalsection 404, because of the larger amount of space between them (e.g.,because of increased longitudinal distance). Thus, the occlusion device400 is capable conforming to a large number of different aneurysm shapesor aneurysm angular takeoff angles or general angulations. The occlusiondevice 400 may be configured to allow for an angle A of between 90° and180°, or between about 135° and about 180°. Thus, the angle A ischangeable to a minimum angle of between about 90 degrees and about 135degrees. If the elongate flexible extension 406 is long enough, anangulation of less than 90° may even be possible, which might occur insome aneurysms with very odd shapes. The substantially flattenedportions may have slight angulations or tapers, as do the substantiallyflattened portions 220, 224, 276, 278 of FIGS. 2-3 or those in 10-11,with the longitudinal space increasing toward the outer diameters, suchthat the angle A (FIG. 14) is decreased even further. The totallongitudinal length of the flexible extension 406 can be between about0.5 mm and about 30 mm, or between about 0.5 mm and about 25 mm, orbetween about 1 mm and about 10 mm, or between about 1 mm and about 6mm, or between about 1 mm and about 3 mm. For cerebral aneurysms, theocclusion device 400 may be configured such that the proximal section402 and the distal section 404 are each substantially hemispherical inshape, but that the flexible extension, when straight, provides anelongated, revolved oval profile. For example, with the proximal section402 and the distal section 404 each having a hemisphere shape of about 6mm in diameter, a 1 mm long flexible extension 406 begets a 7 mm long by6 mm diameter implant. A 2 mm long flexible extension 406 begets an 8 mmlong by 6 mm diameter implant. A 3 mm long flexible extension 406 begetsa 9 mm long by 6 mm diameter implant. A wide range of sizes is possible,and the diameter of the proximal section 402 may differ from thediameter of the distal section 404 or they may be substantially the sameas each other.

FIG. 15 illustrates an occlusion device 410 implanted within anangulated sidewall aneurysm 19 via a delivery catheter 417. Theocclusion device 410 is similar to the occlusion device 400 of FIG. 14,except the elongate extension 416, extending between the proximalsection 412 and the distal section 414, has a bellows configuration thatfurther aids its bendability. Both the inner and outer layer of the meshtube may include the bellows-type feature, or only the outer layer mayinclude this feature. In alternative embodiments, the flexible section406 or elongate extension 416 (e.g., comprising a bellows-type feature)can have an outer diameter that varies along its longitudinal axis. Forexample, the outer diameter may get gradually smaller in the center andlarger on the ends and thus have a concave cylindrical shape orhourglass shape. Alternatively, the outer diameter may get graduallylarger in the center and smaller on the ends and thus have a convexcylindrical shape or American football shape. FIG. 16 illustrates anocclusion device 450 implanted within an aneurysm 452. The aneurysm 452is terminal to a main artery 454, and several connecting arteries 456,458, 460, 462. The occlusion device 450 of FIG. 16 has a proximalsection 464 and a distal section 466, separated by an elongated flexibleextension 468. The proximal section 464 includes a hemispheric proximalend 470 and a concavity 472 distally, opposite the proximal end 470. Thedistal section 466 includes a hemispheric distal end 474 and a concavity476 proximally, opposite the distal end 474. The distal section 466 andthe proximal section 464 are each able to pivot (away from thelongitudinal axis) in relation to the elongated flexible extension 468,which allows the occlusion device 450, when delivered into the aneurysm452, to conform to the shape of the inner contours of the aneurysm 452,and thus more snugly fit into the aneurysm 452. As shown in FIG. 16, anapex 478 the distal section 466 of the occlusion device 450 is slightlypivoted back, and to the right. The proximal section 464 is slightlypivoted forward. The proximal section 464 has a maximum diameter that islarger than the diameter or transverse dimension of the aneurysm neck480. The maximum diameter of the proximal section 464 may also beconfigured to be oversized in relation to the aneurysm sac, in order toapply a gripping radial force. The same is true of the distal section466. Once in the preferred position within the aneurysm 452, theocclusion device 450 is then detached from the pusher 415.

FIG. 17 illustrates an occlusion device 482 being implanted within ananeurysm 484. The occlusion device 482 of FIG. 17 is similar to theocclusion device 200 of FIGS. 1-2, but has slightly differentdimensions. As the occlusion device 482 is implanted within theaneurysm, the distal section 486 and the proximal section 488 arecompressed longitudinally together. The waist 490 is able to deformsomewhat (e.g., shorten and widen) to allow the dynamic shaping of theocclusion device 482 to occur when implanted into the aneurysm 484. Theproximal section 488 is forced (straight arrow) against the neck 492.The substantially flattened portion 494 of the proximal section 488 andthe substantially flattened portion 496 of the distal section 486 areeach able to flex to form ring-shaped concavities. The flexing acts as aspring, to maintain the force of the proximal section 488 against theneck 492. An occlusion device 401 having a relatively wider waist 403and relatively longer flexible extension 405 between its proximalsection 407 and its distal section 409. is shown in FIG. 18. The waist403 of the occlusion device of FIG. 18 has a circumferentially extendingconcavity (hourglass shape) and comprises a hemispherical proximal face411 and a hemispheric distal face 413. The occlusion devices of FIGS.16-18 are shown still coupled to the pusher 415 and being deliveredthrough a delivery catheter 417. FIGS. 19-21 illustrate three differentconfigurations of an occlusion device 700. In FIG. 19, the occlusiondevice, as heat-formed, is in a completely unrestrained, expandedconfiguration. In FIG. 20, the occlusion device is constrained within amicrocatheter lumen 742. In FIG. 21, the occlusion device has beendelivered into an aneurysm 748.

FIG. 19 illustrates an occlusion device 700 comprising a proximalsection 702 and a distal section 704 and a waist 722, all constructed ofa single, continuous dual layer mesh. The occlusion device 700 isconstructed from an inverted mesh tube 706 having a first end, a secondend, and a wall (as in the occlusion device of FIGS. 1-2). The invertedmesh tube 706 extends on an outer layer 712 past a proximal end 714 ofthe proximal section 702 and along a hemisphere shape 716 to a maximumdiameter portion 718 having an acute angulation 719. From the maximumdiameter portion 718, the outer layer 712 extends radially inward alonga substantially flattened portion 720 to the central waist 722. Theouter layer 712 then extends radially outward along a substantiallyflattened portion 724 of the distal section 704 to a maximum diameterportion 726 having an acute angulation 727 to a hemisphere shape 728 toa distal end 730 of the occlusion device 700. The hemisphere shape 728is configured to contact at least a portion of an aneurysm dome. Themaximum diameter portion 726 has a diameter that is about equal to thediameter of the maximum diameter portion 718, but in other embodiments,they may differ. At the distal end 730, the wall 709 is invertedinwardly at an inversion fold 732, which creates a distal orifice 734and an internal volume 736. The wall 709 transitions at the inversionfold 732 from the outer layer 712 to an inner layer 738 which followsthe contours of the outer layer 712 from the distal orifice 734 to thefirst end. The occlusion device 700 is shown coupled to an elongatepusher 701 and a marker band 705.

In FIG. 19, the occlusion device 700 is shown unrestrained. Thus, if themesh tube 706 is formed of at least some nickel-titanium, or shapememory alloy, filaments, braided together, the shape shown in FIG. 19can be heat formed, as described herein. The occlusion device 700, inits compressed configuration, is shown in FIG. 20, inserted through thelumen 742 of a delivery catheter 740 having a distal end 744 and aproximal end 746. FIG. 21 shows the occlusion device 700 within ananeurysm 748 having a neck 750 and a dome 752. The proximal section 702and a distal section 704 are each deformed from contact with theaneurysm wall 754, thus confirming to the aneurysm wall 754 in a snugmanner. The overall length L2 of the occlusion device 700 becomes lessthan the original length L₁ (FIG. 19) because of longitudinalcompressive forces F applied in return by the aneurysm wall 754. Thus,the overall shape of the occlusion device within the aneurysm 748 inFIG. 21 becomes more spherical than that of the unrestrained shape inFIG. 19. The proximal end 714 and the marker band 705 are at or adjacentthe neck 750 of the aneurysm 748, while the distal section 704 isadjacent the dome 752. FIG. 21 also shows a remnant 703 of the pusher701 after detachment has occurred. In some embodiments, no remnant ofthe pusher 701 remains after detachment. The occlusion device 700 isvery conformable with different aneurysmal shapes and sizes. Because ofthis, the occlusion device 700 may also fit into an aneurysm that islongitudinally longer and diametrically narrower than the aneurysm 748of FIG. 21. It may also fit into an aneurysm that has a significantlynon-symmetric shape.

Turning to FIG. 22, an occlusion device 550 is constructed from aninverted mesh tube 552 having a first end 554, a second end 556, and awall 558. The inverted mesh tube 552 extends on an outer layer 560 fromthe second end 556 past a proximal end 562 of the proximal section 564and along a lower mushroom shape 566 to a maximum diameter portion 568.From the maximum diameter portion 568, the outer layer 560 extendsradially inward along the mushroom shape 566 to a first central waist570. The outer layer 560 then extends radially outward along a globularportion 572 having a maximum diameter potion 574 and then to a secondcentral waist 576. Though the globular portion 572 of the occlusiondevice 550 is relatively short and wide, in other embodiments, theopposite might be true, with the globular portion 572 having more of anAmerican football shape. In other embodiments, the golobular portion 572may have a generally spherical shape. The outer layer 560 then forms anupper mushroom shape 578 having a maximum diameter 580 to a distal end582 of the occlusion device 550. The hemisphere shape 584 of the uppermushroom shape 578 is configured to contact an aneurysm dome. Themaximum diameter 580 is about equal to the maximum diameter 574, but inother embodiments, they may differ. The occlusion device 550 issubstantially cylindrically symmetric around a central axis Z. However,in alternative embodiments, there may be certain portions of asymmetry,such as one or more indented or extended feature at a particularlocation in a perimeter. At the distal end 582, the wall 558 is invertedinwardly at an inversion fold 586, which creates a distal orifice 588and an internal volume 590. The wall 558 transitions at the inversionfold 586 from the outer layer 560 to an inner layer 592 which followsthe contours of the outer layer 560 from the distal orifice 588 to thefirst end 554. The occlusion device 550 is fabricated as an invertedmesh tube 552 having a simple straight elongate configuration, and issubsequently formed into the shape shown in FIG. 22 and heat set intothis shape. Each of the three sections, a proximal section 594, acentral section 596, and a distal section 598, are shown in FIG. 22 intheir expanded configurations, but are configured to be compressed orcompacted within the lumen 148 of a delivery catheter 150 (e.g.,microcatheter. The proximal end 562, located on the lower portion of theproximal section 594 has a flat surface 599 or substantially flatsurface, and is configured for engaging, and even gripping, the aneurysmneck at the interior portion of the aneurysm. The engagement of theaneurysm neck by the flat surface 599 or substantially flat surface mayhelp seal the aneurysm and help prevent an endoleak. The globularportion 572/central section 596 is configured to allow the angulationbetween the proximal section 594 and the distal section 598, whileproviding some body, or a stop/limit in between.

In some embodiments, one or more of the proximal section 594, centralsection 596, or distal section 598 may comprise some nickel-titaniumalloy filaments and some radiopaque elements, comprising platinum, gold,tantalum, or alloys of any of these or other radiopaque materials. Insome embodiments, the filaments may comprise drawn filled tubes, such asthose comprising a nickel-titanium alloy outer wall and a platinum core.The radiopaque material allows the occlusion device 550 to be visible onradiographs or fluoroscopy. The occlusion device 550 may be configuredby controlling how much radiopaque material is used, by either the ratioof radiopaque filaments to non-radiopaque filaments, or by the amount ofplatinum core in the drawn filled tubes. In this manner, the occlusiondevice 550 can be selectively fabricated to be sufficiently visible, butnot over visible, e.g., overly bright, such that other objects areobscured. In some embodiments, whether any of the filaments compriseradiopaque materials or not, a marker band may be attached to the firstend 554 and/or second end 556 of the inverted mesh tube 552, by adhesiveor epoxy bonding, or swaging, welding or other mechanical attachment.

FIG. 23 illustrates an occlusion device 600 having an invertedmushroom-shaped proximal section 602, a globular central section 604,and a mushroom-shaped distal section 606 having a distal apex 608. Eachof the sections 602, 604, 606 are separated by central waists 608, 610.Sections 602, 604 are separated by central waist 608 and sections 604,606 are separated by central waist 610. Each of the sections 602, 604,606 are formed from braided mesh 607 having different stiffnesscharacteristics from each other. Though the sections 602, 604, 606 arefully braided, the braiding is only shown in windows 612, 614, 616 forsimplicity. The proximal section 602 is braided such that it is stifferthan either the central section 604 or the distal section 606. Theproximal section 602 may be braided by larger diameter filaments, and/ormay be braided with larger braid angles, to achieve the increasedstiffness. The increased stiffness is configured for securely wedging orsetting against the aneurysm neck, for example, to achieve betterclosure or disruption at the entry to the aneurysm. The distal section606 is braided such that it is less stiff/more flexible than either thecentral section 604 or the proximal section 602. The distal section 606may be braided by smaller diameter filaments, and/or may be braided withsmaller braid angles, to achieve the decreased stiffness. The decreasedstiffness is configured for softly setting against the aneurysm dome.This is particularly helpful in avoiding a rupture of an aneurysm, forexample, a high-risk aneurysm. A high-risk aneurysm may have asubstantially large diameter, or a substantially thin wall at the dome.Another high-risk aneurysm may be a previously ruptured aneurysm thathas at least partially healed, but which may be prone to rerupture. Thecentral section 604 may be braided by filaments, and/or may be braidedwith braid angles, that achieve an intermediate stiffness to theproximal section 602 and the distal section 606. Changes inwire/filament diameter may created after forming the braided mesh 607from a single set of wires, by adjusting or rearranging the braidcrossings. In some embodiments, the distal section 606 may besubsequently etched (chemical etch, photochemical etch) to decrease theoverall wire diameter and decrease the stiffness. In some embodiments,both the distal section 606 and the central section 604 are etched in afirst etching operation. Then, only the distal section 606 is etched ina second etching operation. This, as originally formed, the proximalsection 602, central section 604, and distal section 606 are formed fromwires having the same diameter, but after the two etching operations,the distal section 606 has smaller diameter wires than the centralsection 604 and the central section 604 has smaller diameter wires thanthe proximal section 602. Thus, in some embodiments, the distal section606 may be made more flexible than the proximal section 602 via etchingalone.

FIG. 24 illustrates an occlusion device 1000 having a proximal end 1002and a distal end 1004 and configured for placement within an aneurysm.The occlusion device 1000 comprises a lower portion 1006 having aproximal outer diameter A and a distal outer diameter B and a taperedfrustoconical section 1008 extending between diameter A and diameter B.In some embodiments, the lower portion 1006 is circular, withsubstantially the same diameter at any transverse slice (around theperimeter). In other embodiments, the lower portion 1006 isnon-circular, and may comprise an ellipse, an oval, a polygon or othershapes. The tapered frustoconical section 1008 is configured to belarger than a maximum transverse dimension of an opening into theaneurysm (the neck portion) at at least some portion between A and B. Insome embodiments, the diameter A is configured to be larger than amaximum transverse dimension of an opening into the aneurysm (the neckportion). Thus, the lower portion 1006 is configured to completely coverthe neck portion, and thus to cause stagnation of blood within theaneurysm, leading to occlusion. The occlusion device 1000 is constructedfrom a mesh (braided) Nitinol (nickel-titanium alloy) tube 1005 that isinverted on itself. The mesh tube 1005 has a first end and a second end.The second end is folded back over the outer diameter of the first endthus providing an outer facing surface 1003 and an inner facing surface(not visible in FIG. 24). The mesh tube 1005 is heat-formed such thatthe occlusion device 1000 comprises several expanded portions: the lowerportion 1006, an upper portion 1010, and an intermediate waist portion1012. The upper portion 1010 has a length L, a maximum diameter C_(MAX)and a minimum diameter C_(MIN). The waist portion 1012 has a diameter Dand a length g.

Particular ratios of the dimensions of the occlusion device 1000 havebeen found to be effective in creating a simple, easily-formed structure(body) that is particularly suited to be placed within aneurysms thatmay have at least one elongated dimension. For example, an aneurysm thatis deep and narrow, or an aneurysm that is wide and short. The length ofL of the upper portion 1010 may range from between about 1 mm to about25 mm. The diameter C may range from between about 1 mm and about 25 mm.The diameter B may range from between about 1 mm and about 25 mm. Thediameter A may range from between about 1 mm and about 24 mm. Generally,the diameter C is between about 50% to about 100% of the diameter B.Furthermore, generally, the diameter A is between about 50% to about100% of the diameter B. In some embodiments, the diameter A is betweenabout 70% and about 90% of the diameter B.

As formed (e.g., heat-formed), the occlusion device 1000 has an expandedconfiguration (shown in FIG. 24) and a collapsed configuration,configured for delivery through the lumen of a delivery catheter (e.g.,microcatheter). The occlusion device 1000 comprises two mesh layers,provided by the outer facing surface 1003 and the inner facing surface.In some embodiments, the occlusion device 1000 may comprise somenickel-titanium alloy filaments and some radiopaque elements, comprisingplatinum, gold, tantalum, or alloys of any of these or other radiopaquematerials. In some embodiments, the filaments may comprise drawn filledtubes (DFT), such as those comprising a nickel-titanium alloy outer walland a platinum core. The radiopaque material allows the occlusion device1000 to be visible on radiographs or fluoroscopy. The occlusion device1000 may be configured by controlling how much radiopaque material isused, by either the ratio of radiopaque filaments to non-radiopaquefilaments, or by the amount of platinum core in the drawn filled tubes.In this manner, the occlusion device 1000 can be selectively fabricatedto be sufficiently visible, but not over visible, e.g., overly bright,such that other objects are obscured. In some embodiments, whether anyof the filaments comprise radiopaque materials or not, a marker band maybe attached to the proximal end 1002 of the occlusion device 1000, byadhesive or epoxy bonding, or swaging, welding or other mechanicalattachment. The drawn filled tubes (DFT) may each have a platinum corethat has a cross-sectional area that is between about 10% and about 70%of the total cross-sectional area of the DFT. In some embodiments, all(100%) of the filaments may comprise DFTs. In other embodiments, between50% and 100% of the filaments may comprise DFTs, with the remainder ofthe filaments comprising only nickel-titanium alloy.

Turning to FIG. 25, the occlusion device 1000 may be coupled at or nearits proximal end 1002 to a pusher 152, having a distal end 154 and aproximal end 156. The pusher 152 may comprise a wire, a hypo tube, oranother elongate structure having column support is detachably coupledat its distal end 154 to the proximal end 1002 of the occlusion device1000. A detachable joint 158 may comprise one of a number of detachmentsystems, including but not limited to pressurized detachment,electrolytic detachment mechanisms, hydraulic detachment mechanisms,mechanical or interlocking detachment mechanisms, chemical detachmentmechanisms, heat-activated detachment systems, or frictional detachmentsystems. In any of the embodiments disclosed herein, alternativedetachable joint may be employed, such as the detachable jointsdisclosed in co-pending U.S. patent application Ser. No. 16/840,410,filed on Apr. 5, 2020, and entitled “Systems and Methods for TreatingAneurysms” and in co-pending U.S. patent application Ser. No.16/840,412, filed on Apr. 5, 2020, and entitled “Systems and Methods forTreating Aneurysms,” both of which are hereby incorporated by referencein their entirety for all purposes. During delivery, the pusher 152 isheld on its proximal end 156 by a user and pushed in a forwardlongitudinal direction in order to advance the occlusion device 1000 tothe distal end of a delivery catheter (e.g., a microcatheter) having adelivery lumen. The delivery catheter may also include a proximal hub,such as a luer connector.

FIG. 26 illustrates a first view of the occlusion device 1000 deliveredinto a first aneurysm configuration 1020 comprising an aneurysm 1022, aneck 1024, a first parent vessel arm 1026, a second parent vessel arm1028, and an additional connecting vessel 1030. FIG. 27 illustrates adifferent view. The waist portion 1012 allows some flexure between theupper portion 1010 and the lower portion 1006, and thus the upperportion 1010 is able to be somewhat compressed into the lower portion1006, as seen in FIGS. 26 and 27. Thus, the lower portion 1006 protectsand covers the neck 1024 of the aneurysm 1022 while the upper portion1010 allows the occlusion device 1000 to adapt to the shape of theaneurysm 1022 for a snug by safe fit. The waist portion 1012 also actsas a shock absorber.

FIG. 28 illustrates an occlusion device 800 also comprising an invertedmesh tube 802 and having an outer layer 804, an inner layer 806, and aninversion fold 808, which creates a distal orifice 810, and serves asthe transition between the outer layer 804 and the inner layer 806. Theinverted mesh tube 802 has a first end 812 and a second end 814. Theocclusion device 800 includes a proximal section 816, a distal section818, and an intermediate section 820. The proximal section 816 has asubstantially flattened portion 822, and the distal section 818 has aglobular shape 824, configured to contact an aneurysm dome. Theintermediate section 820 also has a globular shape 826. There is a waist828 between the proximal section 816 and the intermediate section 820,and a circumferentially extending concavity 830 between the distalsection 818 and the intermediate section 820. The proximal section 816includes a proximal concavity 832 concavity, which is configured toclear a marker band 834. The proximal section 816 has a maximum diameter836 configured to grip and internal wall of an aneurysm. The occlusiondevice 800 comprises a cover 838 configured to seat adjacent a neck ofthe aneurysm. In some embodiments, the cover 838 is circular, withsubstantially the same diameter at any transverse measurement around theperimeter. In other embodiments, the cover 838 is non-circular, and maycomprise an ellipse, an oval, a polygon or other shapes. In thenon-circular embodiments, the cover 838 comprises a minimum transversedimension and a maximum transverse dimension. In the particular case ofan ellipse or an oval shape, the cover 838 comprises a major diameterand a minor diameter. The minor diameter or minimum transverse dimensionis configured to be larger than a maximum transverse dimension of anopening into the aneurysm (the neck portion). Thus, the cover 838 isconfigured to completely cover the neck portion, and thus to causestagnation of blood within the aneurysm, leading to occlusion. The cover838 is constructed from a mesh (braided) Nitinol (nickel-titanium alloy)tube 840 that is inverted on itself. The mesh tube 840 has a first end842 and a second end 844. The second end 844 is folded back over theouter diameter of the first end 842. The mesh tube 840 is heat-formedsuch that cover 838 comprises an expanded portion 843 and the first end842 and second end 844 comprise unexpanded (or partially expanded)portions. The cover 838 is fabricated as an inverted mesh tube 840having a simple straight elongate configuration, and is subsequentlyformed into the shape shown in FIG. 28, and heat set into this shape.For example, the inverted mesh tube 840 may be constructed as a singlelayer mesh tube formed of at least some nickel-titanium alloy filaments,and then inverted on itself. The inverted mesh tube 840 may then beplaced into a die or mold comprising one or more pieces, to hold it inthe shape of the cover 838. Then, the cover 838 may be subjected to anelevated temperature and then cooled, to lock in the shape, resulting ina cover 838 having at least some superelastic properties.

The occlusion device 800 may comprise any of the materials and be madewith any of the processes described in relation to the occlusion device200, or any other of the occlusion devices described herein. Theocclusion device 800 is configured to have flexing or articulatingcapabilities at the waist 828 and at the circumferentially extendingconcavity 830 which thus allow the proximal section 816, the distalsection 818, and the intermediate section 820 to bend and conform toaneurysms of complex and irregular shapes. The maximum diameter 836 isconfigured to apply a radial force to the aneurysm wall to keep theocclusion device 800 in place, while the cover 838 facilitatesthrombosis and closure of the aneurysm at the neck.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments may be devised withoutdeparting from the basic scope thereof. The filament diameter of thefilaments comprising any of the mesh material (e.g., mesh tube includinginverted mesh tubes) described herein may be between about 0.0004 inchand about 0.003 inch, or between about 0.0005 inch and about 0.002 inch,or between about 0.0006 inch and about 0.002 inch, or between about0.0006 inch and about 0.0015 inch. The drawn filled tubes (DFT) maycomprise between 0% and 100% of the total strands/filaments in any ofthe braided/mesh tubes. In some embodiments, the drawn filled tubes(DFT) comprise about 50% to about 100% of the total filaments of thecover and about 50% to about 100% of the total filaments of each of thedoubled-over or looped tubular mesh. The radiopaque core of each of atleast some of the drawn filled tubes has a cross-sectional area that isbetween about 10% and about 70% of the total cross-sectional area of theeach of at least some of the drawn filled tubes, or between about 51%and about 70% of the total cross-sectional area of the each of at leastsome of the drawn filled tubes. In some embodiments, NiTi #1-DFT® wireproduced by Fort Wayne Metals Research Products Corp. (Fort Wayne, Ind.USA) may be utilized. The filaments may be braided with patterns havingfilament crossings that are in any one or more of the following ratiosof filaments: 1×1, 1×2, 2×1, 2×2, 2×3, 3×2, 3×3, etc. (e.g., warp andweft). Any low, moderate, or high pick counts may be used, for example,between about 15 picks per inch and about 300 picks per inch, or betweenabout 20 picks per inch and about 160 picks per inch. Any of thefilaments or any of the portion of the occlusion devices may be coatedwith compounds that enhance endothelialization, thus improving thehealing process when implanted within the aneurysm, and optimizingocclusion. The pusher and occlusion device configurations presentedherein may also be used for in other types of implantable devices, suchas stents, flow diversion devices, filters, and occlusion devices forstructural heart defects.

Additional materials may be carried on the cover of the occlusiondevice, or any other proximal portion of the occlusion device, andconfigured to face opposite the aneurysm neck. In some embodiments, thematerial on the occlusion device may comprise a biological layer,configured to encourage growth. In some embodiments, the biologicallayer may comprise antibodies, in order to accelerate the formation ofan endothelial layer, for example, by attracting endothelial progenitorcells (EPCs). In some embodiments, the biological layer may comprise anatural membrane or structure, such as a membrane, such as a membranefrom an ear, or a cornea, or an ultra-thin piece of ligament, or even apiece of blood vessel wall. In some embodiments, the material on theocclusion device may comprise a polymer layer configured to act as asimulated arterial wall. In some embodiments, the polymer layer maycomprise polytetrafluoroethylene, such as expandedpolytetrafluoroethylene (ePTFE), such as that used in grafts. Occlusiondevices as described herein may incorporate biological or polymericlayers, such as those described in co-pending U.S. patent applicationSer. No. 16/840,415, filed on Apr. 5, 2020, and entitled “Systems andMethods for Treating Aneurysms,” which is hereby incorporated byreference in its entirety for all purposes.

The ranges disclosed herein also encompass any and all overlap,sub-ranges, and combinations thereof. Language such as “up to,” “atleast,” “greater than,” “less than,” “between,” and the like includesthe number recited. Numbers preceded by a term such as “approximately”,“about”, and “substantially” as used herein include the recited numbers(e.g., about 10%=10%), and also represent an amount close to the statedamount that still performs a desired function or achieves a desiredresult. For example, the terms “approximately”, “about”, and“substantially” may refer to an amount that is within less than 10% of,within less than 5% of, within less than 1% of, within less than 0.1%of, and within less than 0.01% of the stated amount.

For purposes of the present disclosure and appended claims, theconjunction “or” is to be construed inclusively (e.g., “an apple or anorange” would be interpreted as “an apple, or an orange, or both”; e.g.,“an apple, an orange, or an avocado” would be interpreted as “an apple,or an orange, or an avocado, or any two, or all three”), unless: (i) itis explicitly stated otherwise, e.g., by use of “either . . . or,” “onlyone of,” or similar language; or (ii) two or more of the listedalternatives are mutually exclusive within the particular context, inwhich case “or” would encompass only those combinations involvingnon-mutually-exclusive alternatives. For purposes of the presentdisclosure and appended claims, the words “comprising,” “including,”“having,” and variants thereof, wherever they appear, shall be construedas open-ended terminology, with the same meaning as if the phrase “atleast” were appended after each instance thereof

What is claimed is:
 1. An apparatus for treating an aneurysm in a bloodvessel, comprising: an occlusion element configured to be releasablycoupled to an elongate delivery shaft, the occlusion element comprisingan inverted mesh tube having an outer layer and an inner layer, theouter layer transitioning to the inner layer at an inversion fold,wherein at least the outer layer is formed into an expanded shape havinga proximal section having a first diameter, a distal section having asecond diameter, and a waist portion having a third diameter, whereinthe third diameter is less than the first diameter and the thirddiameter is less than the second diameter.